Answer:
The speed of a wave is a property of the medium changing the speed actually requires a change in the medium itself. If the medium does not change as a wave travels, the wave speed is constant.
TO CALCULATE IT
Wave Speed Formula
Speed of the tsunami (meters/second) is equal to the square root of g (the acceleration due to gravity, which a constant 9.81 meters/second) times the water depth (d) at which the disturbance occurred (meters).